1. Field of the Invention
The present invention relates generally to data communication devices, and in particular, to a power shut-off and recovery circuit for use with data communication devices.
2. Background Art
Computer networks facilitate communication between individuals, businesses, and other entities. Computer networks include communication devices that support the communication of data from a sender to a receiver or data terminal. These communication devices include hubs that join communications lines together in a star configuration, routers that make decisions about which of several paths network traffic (in the form of data packets) will follow, repeaters that copy electrical signals from one Ethernet to another to extend the transmission distance, and bridges that connect two or more networks and forward packets among them.
FIG. 1 illustrates a conventional network system which includes a communication device, which can be a hub, a repeater, a router or a bridge. The communication device has a plurality of ports PORT0, PORT1, PORT2 . . . PORTN through which communication lines can be connected to a corresponding number of data terminals DT0, DT1, DT2 . . . DTN.
One disadvantage with conventional communication devices is that they are powered twenty-four hours-a-day even though the network is actually in use for only a specific number of hours during the day. In other words, since a communication device is only used when two or more users (i.e., data terminals) communicate via the communication device, the communication device is typically not used except during office hours. Unfortunately, these communication devices do not have any shut-off and recovery mechanism. This leads to two drawbacks. First, by keeping these communication devices on and powered continuously, the maintenance costs (e.g., electricity costs) for these devices increase, and power and energy are unnecessarily wasted. Second, by continuously powering these devices twenty-four hours-a-day, seven days a week, the electronic parts in these devices experience a shorter life than parts in a device that is powered only periodically. In other words, continuous and prolonged operation makes these communication devices more susceptible to damage from over-heating, wear, and device failure.
Thus, there still remains a need for a power shut-off and recovery mechanism for data communication devices so that unnecessary power consumption is curbed, and the life of the communication device is lengthened.